A registry is a directory for storing settings and options for software operating within an operating system. For example, the Windows® operating systems by Microsoft Corporation includes a directory file known as the Windows registry which contains the information and settings that are required by hardware, operating system software, and application software, as well as storing user preferences and settings. A registry file serves to locate all program and hardware settings and constant values in a single file structure.
The Windows registry contains two basic elements: keys and values. Registry keys are similar to file folders. In addition to values, each key can contain subkeys which may contain further subkeys. Keys are referenced in a syntax similar to Windows path names using backslashes to indicate levels of hierarchy. Registry values are name/data pairs stored within keys. Values are referenced separately from keys. In the Windows registry, values can be string values, binary data, unsigned 32-bit integers, UNICODE values, multi-string values, lists and 64-bit integer values (in Windows 2000 and later). The Windows registry is constructed as a database offering database-type functions.